我是第一次使用ROS，而且我正在读一本书以开始我的软件包。但是输入catkin_make后出现错误。
我已经完成了hello_world_node.cpp文件和已编辑的CMakeLists.txt文件。
Base path: /home/elsayed/catkin_ws
Source space: /home/elsayed/catkin_ws/src
Build space: /home/elsayed/catkin_ws/build
Devel space: /home/elsayed/catkin_ws/devel
Install space: /home/elsayed/catkin_ws/install
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#### Running command: "make cmake_check_build_system" in "/home/elsayed/catkin_ws/build"
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#### Running command: "make -j4 -l4" in "/home/elsayed/catkin_ws/build"
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make[2]: *** No rule to make target 'my_first_ros_pkg/CMakeFiles/hello_world_node.dir/build'. Stop.
CMakeFiles/Makefile2:924: recipe for target 'my_first_ros_pkg/CMakeFiles/hello_world_node.dir/all' failed
make[1]: *** [my_first_ros_pkg/CMakeFiles/hello_world_node.dir/all] Error 2
Makefile:138: recipe for target 'all' failed
make: *** [all] Error 2
Invoking "make -j4 -l4" failed